Clinical pathologic conference

Pulmonary veno-occlusive disease: involvement of pulmonary arteries and review of the literature

Pulmonary vessels from 26 patients with pulmonary veno-occlusive disease were studied histologically and morphometrically. In addition to the well-known obstruction of veins and venules, pulmonary arteries were also narrowed or obliterated in approximately half of the patients. It is unlikely that the arterial intimal fibrosis, which was sometimes as severe as the fibrosis in the veins, was secondary to the venous obstruction; rather, like the venous alterations, it probably resulted from organization of thrombi. It is possible that primary damage to the vascular wall elicited thrombosis. Such an injury may also have caused the arterialization of the venous walls, a common finding that cannot always be explained by distal narrowing of larger veins. Although the etiology of pulmonary veno-occlusive disease is obscure, it seems increasingly likely that multiple noxious agents may induce this condition. In children no predilection for either sex has been observed, but in adults, men are affected twice as often as women.

Pulmonary venoocclusive disease

Pulmonary venoocclusive disease has been established as a definite clinical entity characterized by congestive cardiac failure with pulmonary arterial hypertension, chronic interstitial pulmonary edema, and normal wedge pressure on cardiac catheterization. This disease was diagnosed and confirmed in a patient during life. A review of the 32 patients reported earlier has been done in an attempt to fine possible etiological agents. Early recognition and treatment with anticoagulants, methylprednisolone, aspirin, and dipyridamole may improve the prognosis.

Pulmonary veno-occlusive disease. Entity or syndrome?

Pulmonary veno-occlusive disease is a rare and usually fatal condition in which there is gradual obliteration of the pulmonary veins and venules. Without a lung biopsy the clinical diagnosis of this disease is difficult. If there is pulmonary hypertension with roentgenographic signs of pulmonary edema and of congestion in the absence of signs of increased left atrial pressure, the diagnosis must be considered. The morphologic picture of the lungs is characteristic. The small veins, and sometimes also the major veins, are narrowed or occluded by fibrous tissue, almost certainly on the basis of organized thrombi. Nodular areas of congestion, interstitial fibrosis, and pneumonitis are regularly present. A viral etiology has been suggested in a number of cases. If we may assume, however, that thrombosis of pulmonary veins is the initial event, the possibility has to be considered that this may be elicited by a virus in some patients and by toxic factors or by clotting disorders in others. Pulmonary veno-occlusive disease might then well be a syndrome rather than an etiologic entity.